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Current Shared Image system lacks of supporting for producing dawn
object from a resource created by gl backing factory.

This ability is required in an important API CopyImageBitmapToTexture
from WebGPU.

This patch support ProduceDawn in
SharedImageBackingFactoryGLTexturePassthrough by:

1. Creating an internal used backing buffer and use copyTexutureCHROMIUM
   to copy from original gl backing resource to it. Passthrough command
   buffer rely on ANGLE's support of copyTextureCHROMIUM
2. ProduceDawn on the internal backing buffer.

For validating command buffer, a copyTextureCHROMIUM like API needs to
be implemented.

BUG=1036142,966582

Change-Id: I24ccaaa589d90a7a1101228155c6eafaf173b2e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2073858
Commit-Queue: Shaobo Yan <shaobo.yan@intel.com>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758751}